tpenta

Hi guys,

I just noticed this week that a fan sound was coming from the front of ther car. I assume is is the radiator fan.

When does that fan come on and what turns it off? Is it automatic?

The heating system/AC are off and the oil and water temperatures appear normal. Yet the fan still stays on. Also, it seems to be blowing air out of the front tire wells.

Please explain what's going on.

Thank you.

-T

Mike in CA

According to the manual, engine compartment temp is monitored for 30 minutes after the engine is switched off and the engine compartment fan may cycle on and off during that period. The manual also says that the radiator fans in front may start when the engine is switched on, but nothing about them turning on when the ignition is switched off. In fact it sates that it's safe to work at the front of the car as long as the engine is off, but to use extreme caution working in the engine compartment as that fan can start as mentioned above.

tpenta

Thanks but I am talking about it staying on while the engine is on.

I am not sure at what point it comes on while driving and when it turns itself off. It seems a little arbitratry but I assume it's monitoring some temperature reading and switching it on and off as necessary.

Does that make sense?

Also, is it supposed to blow air into the tire wells or is some hose loose maybe?

Thanks,

-T

Mike in CA

Having the radiator fans run when the engine is on, especially if air isn't being forced through the radiators by the car moving, is perfectly normal. They will switch on and off based on temperature, as you mentioned. It's also normal for air to exhaust through the wheel wells; you can see the air exhaust vents just in front of the tires.

tpenta

Thanks Mike.

Unfortunately, I think something is wrong. I just monitored my car on the driveway and noticed only the passenger-side fan is coming on. Isn't that indication of a problem where the one is compensating if the other isn't working?

Thank you.

-T

Mike in CA

Sorry don't know if that's normal or not. Hopefully someone else can help.

larrytrk

I thought 1 fan was for A/C?

Bijan

Neither fan should be on with the engine running but cold, weather should be hot for them to stay on.
AFIK, for 997.2 the A/C radiators cover the other two, water on one side and oil on the other

Edgy01

The a/c radiators are the first encountered from the front. Coolant (EGW) coolers are behind the A/C ones. Same on both sides. There is no oil cooler up there.

tpenta

Sorry, not sure I understand. Are you suggesting that the fan on each side serves different cooling purposes and, if so, it might be normal for each to be on by itself?

Thanks,

-T

Crazy Canuck

Driver faster. Fan won't come on.

Edgy01

Both sides have the same function and should be on together.

Bijan

Thanks Edgy on radiator clarrification
Tpenta, assume each fan has it's own relay (don't have 997 manual handy, remembering my 996), if one is sticking closed, then one fan may come on unnecessarily with engine running.
Worth a try to check. Swap them to see if the other fan stays on.

timothyli

No oil cooler? Is there a transmission oil cooler?

smoove

Do you have a 997.1 or 997.2? If the latter, I had this problem and it was ultimately linked to a wiring short in the passenger seat (I know, totally counter-intuitive). Is your AC working? My AC stopped working at the same time that the fan started coming on (at max RPMs - it was very loud/noticeable).